Seagate insider may sell $79M in stock for taxes

A Seagate Technology executive filed a Rule 144 notice to sell shares mainly to cover tax withholding from recent performance share vesting.

Rhea-AI Filing Summary

Seagate Technology Holdings plc (STX) is the issuer for a notice filed on behalf of William D. Mosley to sell common stock under Rule 144. The notice covers up to 102,784 shares of common stock to be sold through Morgan Stanley, with an aggregate market value of $79,363,744.68, compared with 226,644,518 shares outstanding as of September 15, 2026; this is a baseline figure, not the amount being offered. The shares relate to 177,000 shares of common stock issued on September 14, 2026 due to Performance Share Unit vesting as compensation for services. Recent sales in the prior three months include blocks of 30,000 shares on July 1, 2026 and 30,000 shares on August 3, 2026. The notice states that sales are to be made pursuant to an issuer-mandated sell-to-cover solely to satisfy tax withholding obligations.

Key Figures

Shares subject to Rule 144 notice: 102,784 shares Aggregate market value of securities to be sold: $79,363,744.68 Shares outstanding: 226,644,518 shares +4 more

7 metrics

Shares subject to Rule 144 notice 102,784 shares Common stock to be sold through Morgan Stanley under the notice

Aggregate market value of securities to be sold $79,363,744.68 Value of the 102,784 Seagate common shares covered by the notice

Shares outstanding 226,644,518 shares Seagate common stock outstanding as of September 15, 2026

Performance Share Unit vesting shares 177,000 shares Common stock issued on September 14, 2026 as compensation for services

Sale on July 1, 2026 30,000 shares for $27,444,658.12 Past three-month sale of Seagate common stock by William D. Mosley

Sale on August 3, 2026 30,000 shares for $24,511,131.27 Past three-month sale of Seagate common stock by William D. Mosley

Sale on September 1, 2026 30,000 shares for $24,488,282.26 Past three-month sale of Seagate common stock by William D. Mosley

Key Terms

Rule 144, Performance Share Unit Vesting, sell-to-cover, Attorney-in-Fact

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Performance Share Unit Vesting financial

"Common stock | 09/14/2026 | Performance Share Unit Vesting | Issuer"

sell-to-cover financial

"Sales to be made pursuant to Issuer mandated sell-to-cover solely to satisfy"

Sell-to-cover is when part of newly issued or exercised company stock is immediately sold to pay required taxes and fees, so the recipient keeps the remaining shares. For investors this matters because it reduces the number of shares insiders or employees actually hold after a grant, can create small, routine share sales that aren’t signal of cashing out, and slightly increases share supply on the market—like selling a portion of a paycheck to cover the tax bill.

Attorney-in-Fact regulatory

"Signature | /s/ Dawn Ledbetter. Attorney-in-Fact for William D. Mosley"

An attorney-in-fact is the person or entity given legal authority through a power of attorney to act on behalf of another for specific tasks, such as signing documents, voting shares, or handling transactions. For investors, this matters because it lets a trusted representative make timely decisions or complete paperwork when the owner cannot, much like handing keys to someone to run errands on your behalf—so checks on scope and limits of that authority are important.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What does Seagate Technology (STX) disclose in this Form 144 notice?

The notice reports that William D. Mosley may sell up to 102,784 shares of Seagate common stock under Rule 144, with an aggregate market value of $79,363,744.68, through Morgan Stanley as of September 15, 2026.

How many Seagate (STX) shares are outstanding in this filing?

The filing states that Seagate Technology had 226,644,518 shares of common stock outstanding as of September 15, 2026, providing context for the size of the potential Rule 144 sale.

What recent equity award is related to the Seagate (STX) Form 144 filing?

The securities to be sold relate to 177,000 shares of Seagate common stock issued on September 14, 2026 due to Performance Share Unit Vesting, described as compensation for services from the issuer.

How does the Seagate (STX) filing describe the purpose of the planned stock sales?

The remarks state that sales are to be made pursuant to an issuer mandated sell-to-cover, used solely to satisfy tax withholding obligations, indicating the sales are for tax coverage rather than discretionary liquidation.

What past Seagate (STX) stock sales by William D. Mosley are listed?

Over the prior three months, listed sales include 30,000 shares of common stock on July 1, 2026 for $27,444,658.12 and 30,000 shares on August 3, 2026 for $24,511,131.27, among several additional smaller transactions.

Who signed the Seagate (STX) Form 144 and on whose behalf?

The notice is signed by /s/ Dawn Ledbetter as Attorney-in-Fact for William D. Mosley, indicating it was executed under a power of attorney rather than directly by Mosley.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/15/2026 - 07:56 PM Accepted by SEC EDGAR 09/15/2026 - 07:56 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001388390
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	Seagate Technology Holdings plc
SEC File Number	001-31560
Address of Issuer	121 WOODLANDS AVENUE 5 SINGAPORE SINGAPORE 739009
Phone	65 6412 5172
Name of Person for Whose Account the Securities are To Be Sold	MOSLEY WILLIAM D
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer
Relationship to Issuer	Director

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common Stock	Morgan Stanley 1 New York Plaza 8th Floor New York NY 10004	102784	79363744.68	226644518	09/15/2026	NASDAQGS

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common stock	09/14/2026	Performance Share Unit Vesting	Issuer			177000	09/14/2026	Compensation for services

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
William D. Mosley 474888 Kato Rd Fremont CA 94538	Common Stock	07/01/2026	30000	27444658.12
William D. Mosley 47488 Kato Rd Fremont CA 94538	Common Stock	08/03/2026	30000	24511131.27
William D. Mosley 47488 Kato Rd Fremont CA 94538	Common Stock	08/21/2026	14746	12524373.54
William D. Mosley 47488 Kato Rd. Fremont CA 94538	Common Stock	09/01/2026	30000	24488282.26
William D. Mosley 47488 Kato Rd Fremont CA 94538	Common Stock	09/10/2026	2849	2456436.29
William D. Mosley 47488 Kato Rd Fremont CA 94538	Common Stock	09/14/2026	1870	1460891.50

144: Remarks and Signature

Remarks	Sales to be made pursuant to Issuer mandated sell-to-cover solely to satisfy tax withholding obligations.
Date of Notice	09/15/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Dawn Ledbetter. Attorney-in-Fact for William D. Mosley
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)